The Yellow Pages directory is a well-known business information bridge between buyers and sellers throughout the world. Traditionally the Yellow Pages directory has been a classified paper directory in which the sellers of services and products can have advertisements. Nowadays, the Yellow Pages directories are also available on the Internet so that the users can access the directories on-line with standard web browsers. Further, mobile users can make inquiries to the Yellow Pages directories if the mobile equipment supports a short message service or Internet access.
The Yellow Pages directory contains information about businesses categorized by headings. The categories are defined by type of product or service sold by the various businesses. The same basic information, called a record herein, such as a business name, address and phone number, is provided for each included business. Different Yellow Pages directories are published for different geographical regions (e.g. cities, counties, etc.). There are also various specialized Yellow Pages directories.
EP 0858635 discloses Yellow Pages catalogues or directories of distributed multimedia documents for the Internet. The user can navigate in a virtual reality space by looking up, looking down, turning around, zooming in, or zooming out. Category labels are displayed to the user in a tree structure hierarchy, and the user can make inquiries to the Yellow Pages.
U.S. Pat. No. 6,025,843 discloses an improved user interface for performing computer database searches and filtering search results. The data returned from the database query are displayed as tree structures.
The Yellow Pages directories have different category descriptions and structure in different countries, or even within one country. An example of different category descriptions is shown in FIGS. 1A and 1B. In FIG. 1A, Finnish resource categories include categories F1 to F14 with corresponding category descriptions. The British resource categories include categories E1 to E16 with respective category descriptions. However, both the categories and the category descriptions differ from each other in the Finnish and the British directories. Further, the directories are in different languages. This makes it difficult to create inquiries to these directories. The inquiry must always define a directory-specific category in the language used in the directory resource to be accessed. If the inquirer decides to make the same inquiry to another directory, he/she has to redefine the category in the language used in the other directory. It is thus very difficult for the client to use the information directories available in different countries when he/she is travelling abroad. This disadvantage is particularly essential in mobile information services, since it discourages foreign mobile users from using the information services. Therefore, a need exists for an inquiry mechanism which makes the inquiries to different categorized directory resources easier.